Cold weather garments abound in the retail marketplace today. These garments are constructed from a wide range of materials and in a variety of styles depending on their use. However, their primary function is to keep the user warm while also meeting the diverse demands of various cold weather sports and activities. Such demands include freedom of movement, minimal weight, low bulk, water impermeability, moisture and wind resistance, and, for activities that occur in or around water, buoyancy.
Typical thermal liners for cold weather garments are constructed of multiple layers of material. Normally, they consist of an outer shell, a thermal layer, and an inner liner. When these liners are constructed for use in moderate temperatures, they seem to address most user requirements. However, as temperatures go down, the traditional response is to add material or increase the density of the thermal layer. This approach leads to decreased freedom of movement, added weight and bulk, increased wetting due to perspiration, poorer air circulation inside the garment, and increased manufacturing cost.
Several types of multi-layered garment liners have previously been disclosed. Generally, these liners have the following disadvantages:                (a) To achieve a comfort level at low temperatures, the amount of thermal insulating material has to be increased substantially;        (b) This increase in thermal material adds weight, bulk, and creates difficulty in mass production because of problems associated with cutting, handling, and sewing the bulky liner material typically used such as down, polyester, polygard, etc.;        (c) Increasing amounts of material tend to limit the ability of the garment to respond to changes in temperature resulting in excessive moisture due to perspiration during transition from low to high temperatures;        (d) Manufacturing processes intended to minimize the effects of thickness and bulk result in rigidity and stiffness in the product, thus limiting freedom of movement. Cost is also directly impacted.        
The search for ultra light weight, inexpensive, thermal insulating material for garments has resulted in disclosures such as U.S. Pat. No. 4,583,247 to Fingerhut et.al. (1986) for a composite insulation material. While U.S. Pat. No. 4,583,247 does appear to meet weight, bulk and cost criteria when a single layer of insulation is used, it may not be sufficient to provide thermal protection in very cold temperatures without stacking layer upon layer of composite material to form the inner lining.
U.S. Pat. No. 5,140,721 to Kauffeld (1992) discloses the use of plastic bubble packing sheets to make thermal protective insulating underwear for divers.
U.S. Pat. No. 5,140,721, in its simplest form, takes sheets of bubble packing material and makes them into undergarments for divers. These inner garments have no inner or outer liners, and may or may not be worn over an inner garment.
While acknowledging the ultra light weight and excellent thermal insulating properties of plastic bubble packing material as it is used in U.S. Pat. No. 5,140,721, it is inefficient as the sole element of a thermal garment. When placed against the body, bubble packing material adheres to the skin because of the moisture created through perspiration or the outside environment. Since there is no means for absorbing this excess moisture, the comfort level of the user is degraded. Furthermore, without some type of inner wicking liner or adequate air space, ingress and egress from the fitted garment are severely hampered because of the tendency for plastic bubble packing material to cling to the body. In addition, the absence of an inner liner subjects the bubbles, especially if the non-barrier light weight bubble packaging material is used, to possible rupture. Lastly, bubble packaging material is inappropriate for a diver's dry suit in which minimum buoyancy is a highly desired characteristic.
The traditional method of forming seams in survival or anti-exposure dry suits involves gluing together a butt seam where a rubber-like glue is applied to each of the faces to be butt joined allowing the glue to dry or cure. This method has been found to have inadequate strength, particularly when the composite seams are composed of dissimilar fabric or material such as that for zipper closure tape.
In another method of forming seams, a glued and butted seam of the above type is strengthened by stitching the seams. However, when this method is used and the seam is placed under stress, the needle holes become enlarged allowing water to penetrate through the holes to the interior of the suit. This is sometimes referred to as pin holing. For example, U.S. Pat. No. 3,731,319 to O'Neill (1973) and U.S. Pat. No. 5,802,609 to Garafalo (1998) disclose a suit provided with inturned seals at the neck, ankles, and wrist to make them substantially watertight. However, there is no solution offered to prevent water intrusion due to pin holing.
A further advance in the above glued, butted, and stitched method involves gluing a flexible tape on the inside or on opposite sides of the seam which improves the seam strength and waterproof characteristics. However, with such a method, the tape, when submerged in cold water for extended periods of time, can separate from the stitched joint impacting the integrity of the waterproof seam. In the past, difficulty in formulating an adhesive bonding system that will adhere to a polymer composite such as polyethylene, particularly when using dissimilar materials, prohibited the use of a polymer liner element in watertight garments.
Thus, the need exists for solutions to the above problems with the prior art.